Solar (e.g., photovoltaic) modules are often manufactured in the form of flat rigid structures. To facilitate the performance of the function of generating electricity, solar modules may be mounted in an area exposed to the sun or other source of light. Often, it is desirable to mount solar modules outdoors at an angle from the horizontal so that they will more directly face the sun during peak daylight hours as opposed to modules mounted horizontally. In some applications, it may be desirable to mount a number of solar modules together in an array in order to combine the power generation capabilities of the individual modules. In many instances, it may be desirable that mounting systems for solar module arrays retain the solar modules in place. This may be accomplished by attaching the solar modules to one another in a mounting system and/or by mounting the modules to the mounting system.
For example, U.S. Patent Application Publication No. 2007/0133474 to Mascolo et al. describes a supported solar module assembly including a solar module comprising a solar module and solar module supports including module supports having support surfaces supporting the module, a module registration member engaging the solar module to position the solar module on the module support, and a mounting element. U.S. Pat. No. 6,534,703 to Dinwoodie describes a solar module assembly for use on a support surface comprising a base, a solar module, a multi-position module support assembly, and a deflector.
Solar module assemblies are typically subjected to thermal stress. Thermal stress is a mechanical stress induced in a body when some or all of its parts are not free to expand or contract in response to changes in temperature. For example, on solar module arrays, thermal stresses may generate forces on the modules and the mounting system retaining the modules. In some cases, these forces may cause the modules and/or mounting system to rotate, translate, or otherwise move relative to the underlying surface (e.g., a rooftop). In some cases, thermal expansion and contraction may slide entire solar module arrays across the roof, potentially damaging the roof surface, the mounting system, the modules, etc. Thermal expansion and contraction cycling may result in premature solar module failures, mounting system failures, etc.